Problem:
By default, 'termpastefilter' removes TAB chars when pasting to a :terminal.
Very annoying, and does not improve "security".

Solution:
Drop "HT" from the 'termpastefilter' default.

Problem:
TM_DIRECTORY expands to the directory's basename, losing its parent path.

Solution:
Remove the tail modifier when expanding the current file's directory.
Extend the existing known-variable test to check the full directory path.

AI-assisted

Problem: watchdirs() keeps its state in large nested callbacks in
_watch.lua, which makes its directory tracking logic harder to change.

Solution: Move the backend into its own module and store its state in a
WatchDirs instance. Split setup, event handling and cleanup into
methods. Extend the existing test to cover cancellation while a
directory stat is pending.

AI-assisted

Work towards enabling "flow" layout in most `:help` files.

Since [tables are supported in help](https://github.com/neovim/tree-sitter-vimdoc#tables),
it's now possible to render most help files as ["flow" layout](https://github.com/neovim/neovim/blob/9244da12e400ec0291450a5e9400d995e7a29b83/src/gen/gen_help_html.lua#L86-L88)
instead of the legacy fixed-width layout. Besides [improved HTML rendering](https://github.com/neovim/neovim/pull/42381#discussion_r4285705739),
flow layout will allow `:help` presentation-mode to un-hardwrap text
blocks.

Work towards enabling "flow" layout in most `:help` files.

Since [tables are supported in help](https://github.com/neovim/tree-sitter-vimdoc#tables),
it's now possible to render most help files as ["flow" layout](https://github.com/neovim/neovim/blob/9244da12e400ec0291450a5e9400d995e7a29b83/src/gen/gen_help_html.lua#L86-L88)
instead of the legacy fixed-width layout. Besides [improved HTML rendering](https://github.com/neovim/neovim/pull/42381#discussion_r4285705739),
flow layout will allow `:help` presentation-mode to un-hardwrap text
blocks.

Problem:
After edits move diagnostic ranges, counted jumps resume searching from
their original positions. This can revisit the same diagnostic and hang
the default first/last diagnostic mappings.

Solution:
Advance the search origin using the diagnostic's current logical position.
Test forward and backward counted jumps after inserting or deleting a
line, including jumps to the last or first diagnostic without wrapping.

AI-assisted

Problem:
Accepting an item from another completion source raises an error when its
user_data.nvim table does not contain LSP metadata.

Solution:
Retrieve and guard the nested LSP metadata before accessing its fields.

Cover acceptance of a foreign completion item without LSP metadata.

AI-assisted

Problem:
An empty snippet insertText falls back to the label during selection, but
acceptance clears that label and expands an empty string.

Solution:
Require nonempty insertText before expanding a snippet without textEdit.

Extend the omnifunc acceptance fixture with an empty snippet insertion.

AI-assisted

Problem:
A completion list default edit range can replace the explicit range of an
InsertReplaceEdit, filtering out valid items or changing their replacement.

Solution:
Only synthesize a default text edit when the completion item has none.

Extend the existing itemDefaults test for explicit edits with both range variants.

AI-assisted

Problem:
Snippet completion words and previews prefer insertText even when textEdit
is present, although the actual expansion uses textEdit.newText.

Solution:
Use the text edit before the fallback insertion text in both selectors.

Extend the existing precedence test to check the snippet word and preview.

AI-assisted